My good friend, Alan Rush, once told me of his "system" for evaluating executives. He said that successful outcomes were the result of at least two out of three of his "success criteria" being met in the relationship.
These included, people that were:
Fun to be with
Willing to learn, and
Bigger than the problem
Each successful client relationship we have has at least two of these three criteria, if not all three. It is a good metric to predict success or failure, and make adjustments accordingly. We avoid projects where none of the three are present in the relationship.
Fun to be with means that the person has a sense of humor and humility
Willing to learn means a person has not stopped learning and is open to new ideas
Bigger than the problem describes a person who can step outside of their "system" and look at the problem from a broader more holistic perspective -- also called a "systems thinker"
Alan confirmed this analysis during his Ph.D. work at Stanford where he studied how leaders "take counsel and listen to advise." The most successful leaders he studied had all three of these attributes.